Synthesis And Field Emission Characteristics Of N-Doped SiC One-Dimensional Nanomaterials

In this paper, we studied on the preparation, plasma processing, purifying and the field emission (FE) properties of the N-doped SiC 1-D nanomaterials. This work focuses on the influence of the raw materials ratio, kind and processing time of plasma, purifying processing to products morphology, structure, composition and FE properties. The FE mechanisms affected by the technological conditions were discussed. Followings are the main research contents.N-doped SiC 1-D nanomaterials with high quality were synthesized by chemical vapor reaction (CVR), the best mass ratio of Si-SiO₂ mixture powder to the melamine was 1:3 by studying the effect of the mass ratio on the products. Products obtained under this condition have high purity and uniform diameter, possessing the best FE properties, whose turn on field and threshold field are 1.5 and 3.5 V/μm respectively. The results suggest that the N amount in the products increasing with the melamine added, and the morphology of the products changes along with it. The FE properties of N-doped SiC 1-D nanomaterials are affected by both the N amount and the morphology of the products.The N-doped SiC 1-D nanomaterials were treated by plasma bombarding processing. Influence of plasma bombarding on the FE properties of the products was examined, the chief factors were the kind of the plasma and the bombarding time. It suggested that the surface morphologies of the N-doped SiC 1-D nanomaterials were changed with the plasma bombarding processing, and it is the main reason to improve the FE properties.The N-doped SiC 1-D nanomaterials synthesized by CVR could be purified purified by calcination in combination with subsequent HF etching processing. The best purifying technology was obtained by studying the effect of temperature, holding time, solution concentration of HF and the soaking time on the products. Results suggest that the carbon grains and the SiO₂ coated layers are removed after the purifying processing. FE properties of the products are improved, with turn-on and threshold fields decreased by 1.1 V/μm and 0.6 V/μm, respectively.Based on the necessary analysis, it can be found that FE properties of the SiC 1-D nanomaterials are strongly dependent on their morphologies. Magnetic field shielding effect (MFSE) is proposed for the first to explain the morphology-dependent FE characteristics of straight, felted and curly SiC 1-D nanomaterials.